The present invention relates to water collection pipes placed in bodies of water such as lakes and rivers and used by major manufacturing plants, large cities, irrigation systems and power generation facilities, and particularly to filters that filter water entering the collection pipes. More particularly, the present invention relates to a filter assembly that provides for flow uniformity through a screen of the filter.
Conventional intake filter assemblies typically include an inlet pipe having an open end surrounded by and coupled to a cylindrical screen, which has a central axis that is the same as a longitudinal axis of the inlet pipe. In this way, the cylindrical screen is concentric with the inlet end of the inlet pipe. A typical intake filter assembly may also include a flow modifier pipe positioned concentrically within the inlet pipe and extending beyond the inlet pipe into the cylindrical screen. The flow modifier pipe helps evenly distribute the flow of water through the cylindrical screen over the length of the screen. See, for example, U.S. Pat. No. 6,051,131 to Maxson, the disclosure of which is incorporated by reference herein.
The flow through the cylindrical screen can be uneven over the length of the cylindrical screen. That is, the flow rate through one portion of the intake screen may be different than the flow rate through another portion of the intake screen. An intake filter assembly which more uniformly distributes the flow over the length of the cylindrical screen would be welcomed by users of such filters.
According to the present invention, a submerged intake filter assembly includes a cylindrical screen which has a screen longitudinal axis, a first end, a second end, and an inner screen surface. The submerged intake filter assembly also includes a first end plate and a second end plate coupled to the cylindrical screen at the first end and the second end, respectively. Thus, the first end plate and the second end plate together with the inner screen surface define an interior of the cylindrical screen. The submerged intake filter assembly also includes a primary flow modifier pipe with a diameter that is less than that of the cylindrical screen and a primary longitudinal axis that is parallel to the screen longitudinal axis. The primary flow modifier pipe extends into the interior of the cylindrical screen through the first end plate, thereby forming an annular space between the primary flow modifier pipe and the inner screen surface at the first end of the screen. The submerged intake filter assembly further includes a secondary flow modifier pipe positioned in the annular space and extending into the interior of the cylindrical screen.
In preferred embodiments, the primary flow modifier pipe is either concentric or eccentric with the cylindrical screen at the first end of the screen. A plurality of secondary flow modifier pipes is positioned in the annular space, and extend either the same or different distances into the interior of the cylindrical screen.
Additional features and advantages will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.